Laser marking systems are now in common use for marking materials such as metals, glass, wood, and plastic. Lasers used in such marking systems include diode-pumped solid-state lasers, fiber-lasers, and carbon dioxide (CO2) lasers. Typically a beam from whatever laser is used in the system is steered by a two-axis galvanometer and focused by f-theta optics onto a surface of an object being marked.
Special materials have been developed, and are commercially available, for accepting laser radiation to allow high-speed, high-volume, writing of labels with a laser marking system. One such material is “Laser Markable Label Material 7847” available from 3M Corporation of Minneapolis, Minn. This material is a three-layer polymer material having a white base film with a black surface coating to facilitate absorption of laser radiation. The white base film becomes exposed when the black material is ablated away by laser radiation. The base film is backed by an adhesive layer. A paper liner supports the laminate which can be peeled off when the label is to be applied to the product. The white material can be laser-cut to define the bounds of the label and allow such peeling. Other materials include black-anodized metal aluminum foil, organic materials used in electronics packaging and printed circuit boards, and white paper impregnated with a dye having an absorption band in the near infrared region of the electromagnetic spectrum for absorbing NIR laser radiation. These materials are often supplied in tape form, so that large numbers of separate labels can be generated without having to reload material in the label maker, however these materials can also be supplied in individual sheets or the like.
Even the least expensive laser marking system designed for these label materials has a cost about two orders of magnitude greater than a computer peripheral paper-label printer such as an inkjet printer, which puts such a system beyond the means of the majority of smaller industrial or commercial users. This is somewhat unfortunate as such a system does not require periodic replacement of inkjet or toner cartridges and will function until the laser eventually fails which may only be after tens of thousands of hours of actual use. These materials also have significant advantages over inkjet printed labels in terms of ruggedness and durability. Accordingly, there is a need for a significant reduction in the cost of laser marking systems for label printing and the like.